From patchwork Tue Feb 11 14:47:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 1236419 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=embeddedor.com header.i=@embeddedor.com header.a=rsa-sha256 header.s=default header.b=NHUHDOfc; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48H9xw2DgPz9sRY for ; Wed, 12 Feb 2020 05:18:28 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727936AbgBKSS1 (ORCPT ); Tue, 11 Feb 2020 13:18:27 -0500 Received: from gateway20.websitewelcome.com ([192.185.55.25]:23538 "EHLO gateway20.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727511AbgBKSS1 (ORCPT ); Tue, 11 Feb 2020 13:18:27 -0500 X-Greylist: delayed 1500 seconds by postgrey-1.27 at vger.kernel.org; Tue, 11 Feb 2020 13:18:27 EST Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway20.websitewelcome.com (Postfix) with ESMTP id C6BA84012ECE3; Tue, 11 Feb 2020 10:17:58 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 1ZNkjQrto8vkB1ZNkjP415; Tue, 11 Feb 2020 11:31:32 -0600 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Type:MIME-Version:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=YMSqBvn3OFsv1lNznyX5EeTk3+DH+Esm65JtcIOwnMY=; b=NHUHDOfcZNONgQ1WuY5dZ7AOCh 4mQkzvYwO/yKv3y/vPOypI8iKziwgDe3py2fiDT5L185TEMkA+8G2a0StgViX9Qwj3lRGN7rCloCo a1G2hFqJxJbQveFpv4Jk8e/ogd6GBHWzcs5hw2JCiODZVyQGXIkV14HxbAgx+Dg/7PYG3LaEMXe9p LGFr7/Ffzi1u21i8Du71DskqkRx31jb3D2gJQXPYxxXicXPJyaR9CTeYol4YzRpvPHUUhhbv3bAoT r3q2yGh/8m6EknhOaFtx/7ZRs7LGXkZqROqzdD+BXtMCqmMQDZdk08lh+FDfr5Y5CKwizz/mZG+TJ Xs72lOIA==; Received: from [200.68.141.48] (port=6149 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j1Wm9-002prQ-E0; Tue, 11 Feb 2020 08:44:33 -0600 Date: Tue, 11 Feb 2020 08:47:04 -0600 From: "Gustavo A. R. Silva" To: Thor Thayer , Andy Shevchenko , Wolfram Sang , David Laight Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH v2] i2c: altera: Fix potential integer overflow Message-ID: <20200211144704.GA6461@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 200.68.141.48 X-Source-L: No X-Exim-ID: 1j1Wm9-002prQ-E0 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.68.141.48]:6149 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 0 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Factor out 100 from the equation and do 32-bit arithmetic (3 * clk_mhz / 10) instead of 64-bit. Notice that clk_mhz is MHz, so the multiplication will never wrap 32 bits and there is no need for div_u64(). Addresses-Coverity: 1458369 ("Unintentional integer overflow") Fixes: 0560ad576268 ("i2c: altera: Add Altera I2C Controller driver") Suggested-by: David Laight Signed-off-by: Gustavo A. R. Silva Reviewed-by: Thor Thayer --- Changes in v2: - Update subject and changelog text. - Avoid the need for 64-bit arithmetic at all. drivers/i2c/busses/i2c-altera.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c index 5255d3755411..1de23b4f3809 100644 --- a/drivers/i2c/busses/i2c-altera.c +++ b/drivers/i2c/busses/i2c-altera.c @@ -171,7 +171,7 @@ static void altr_i2c_init(struct altr_i2c_dev *idev) /* SCL Low Time */ writel(t_low, idev->base + ALTR_I2C_SCL_LOW); /* SDA Hold Time, 300ns */ - writel(div_u64(300 * clk_mhz, 1000), idev->base + ALTR_I2C_SDA_HOLD); + writel(3 * clk_mhz / 10, idev->base + ALTR_I2C_SDA_HOLD); /* Mask all master interrupt bits */ altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);